The Mets on Monday announced long-anticipated changes to their home park, moving in portions of the outfield wall as much as 12 feet and lowering the height of the home run line in half, to a uniform 8-feet high throughout the outfield, down from its present 16-foot height.

The original wall measuring 16 feet is structural and cannot be removed, so a new wall will be built in front of the old one. In left field, it will start between the New Era and Caesars signs and angle to the Citi sign in left-centerfield. The new wall will be closer to home plate by approximately four feet in left field and up to 12 feet in deep left-center field.

A new wall will also start in right-center field and extend toward the bullpen, and be as much as approximately 11 feet closer to home plate. And the fence in front of the Mo’s Zone/Modell’s Clubhouse in right field will come in about 10 feet.

The distances from home plate to center field and down the lines will remain the same at Citi Field. Straightaway center is still 408 feet, the left field line is 335 feet, the right field line remains 330 feet. But the power alleys and deep left and right centerfield are where the biggest differences will be. The old dimensions from left to right in these areas were 371 – 384 – 415 – and 378. The new measurements – although not exactly in the same precise spots – are 358 – 385 – 398 – and 375. The biggest difference comes in deep right-center field near the bullpens, moving in from 415 feet to 398.

Mets officials decided to reconfigure the park after studying the data over the 3 years that Citi Field has been in existence to try and make it a “fairer” park for both hitters and pitchers. Using the new revised dimensions, GM Sandy Alderson assessed that the Mets would have hit 81 additional home runs over the three seasons, while opponents would have hit 70.

Alderson also added that lefties had hit just nine opposite-field home runs to left field in three years – and all of them by opposing players.

Citi Field also allowed only 1.33 HR per game last season, and there were only 2 National League parks where players hit fewer – cavernous Petco Park in San Diego (1.23) and the always tough AT&T Park in San Francisco (1.00). And over the three years of its existence, Citi Field was dead last in the major leagues with just 1.43 HR per game.

As a result of reconfiguring the park, the in-play surface area has been reduced by 2%. And the playing surface beyond 300 feet from home plate has been reduced by 5%. A by-product of that could and should spell an improvement defensively in the outfield, which in turn could and should help the pitching staff.

Finally, as a result of moving the walls in while retaining the existing wall, it will create a unique seating section in leftfield between the two walls that will accommodate about 100 fans.

The Mets will also expand the Modell’s Clubhouse in right field to incorporate an outdoor seating area for approximately 40 more fans.